Client Cooperation in Future Wireless Broadband Networks IEEE 802.16 Presentation Submission...
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Transcript of Client Cooperation in Future Wireless Broadband Networks IEEE 802.16 Presentation Submission...
Client Cooperation in Future Wireless Broadband Networks
IEEE 802.16 Presentation Submission Template (Rev. 9) Document Number:
IEEE C802.16-10/0005Date Submitted:
2010-01-10Source:
Kerstin Johnsson, Nageen Himayat, Shilpa Talwar E-mail: [email protected] Intel Corporation
Venue:San Diego, CA, USA
Base Contribution:None
Purpose:For discussion in the Project Planning Adhoc
Notice:This document does not represent the agreed views of the IEEE 802.16 Working Group or any of its subgroups. It represents only the views of the participants listed in the “Source(s)” field above. It is offered as a basis for discussion. It is not binding on the contributor(s), who reserve(s) the right to add, amend or withdraw material contained herein.
Release:The contributor grants a free, irrevocable license to the IEEE to incorporate material contained in this contribution, and any modifications thereof, in the creation of an IEEE Standards publication; to copyright in the IEEE’s name any IEEE Standards publication even though it may include portions of this contribution; and at the IEEE’s sole discretion to permit others to reproduce in whole or in part the resulting IEEE Standards publication. The contributor also acknowledges and
accepts that this contribution may be made public by IEEE 802.16.
Patent Policy:The contributor is familiar with the IEEE-SA Patent Policy and Procedures:
<http://standards.ieee.org/guides/bylaws/sect6-7.html#6> and <http://standards.ieee.org/guides/opman/sect6.html#6.3>.Further information is located at <http://standards.ieee.org/board/pat/pat-material.html> and <http://standards.ieee.org/board/pat >.
Client Cooperation in Future Wireless Broadband Networks
Input for 802-wide Tutorial in March
What is Client Cooperation?
Poor WWAN link
Good WWAN link
Good WLAN link
WWAN BS
Laptop with WWAN & WLAN
MID with WWAN & WLAN
Client Cooperation (CC) is a MAC technique where clients interact to jointly transmit/receive data in wireless environments.
Idea: Exploit client clustering and peer-to-peer communication to transmit/receive data over multiple paths between source and destination.
Benefit: Performance improvement in throughput, capacity and reliability without increased infrastructure cost.
Usage: Clusters of stationary/nomadic clients that share the same WWAN service provider. Peer-to-peer link can be WWAN or WLAN.
Use Cases
Other storesStranger devices in public assembly areas: Users deep inside cafés/stores/airports/arenas with very poor signal quality can receive a rate boost from performing CC with users closer to entrance or windows. Even if café has free WiFi (not all do), there are/will be services that are WiMAX specific, which require broadband rates.
Same client devices at home: Devices with poor signal quality within multi-level homes can receive significant rate increase from other devices belonging to same user in better signal locations.
M2M deployments: Meters in poor locations can receive rate boost and energy savings from meters in better locations, saving the owner deployment costs.
Tall buildings
Business Models for Use Cases
Same client devices – One owner guarantees full participation by all devices
– Net power savings across network
– Rate improvement to devices in poor locations
Stranger devices– Service provider must dimension system based on non-cooperation to
guarantee service
– CC boosts service above minimum guarantees
– Clients encouraged to participate by promise of • Improved total throughput during subscription period
• Improved energy efficiency during low power periods
• Protection from rate degradation during traffic periods and power degradation during low power periods
M2M – same benefits as same client case
CC Architecture Assumptions
• WiMAX between ABS and AMSs; WiFi between AMSs
• One WiFi hop between originating and cooperating AMSs
• All AMSs are associated with the same ABS
• ABS controls WiMAX scheduling
• AMSs controls 3 fundamental protocols of CC: neighbor discovery, cooperator selection/assignment, and cooperation scheduling
Goodput
[3.5]
>8x increase in cell-edge rates with small user clusters• Full-power cooperation (originator & cooperator transmit at max power) outperforms low-
power cooperation (originator transmits low power, cooperator transmits high power) • Gains decrease with increased channel correlation among clients
[5] [6.5]
[Average number of users within WiFi range]
Power ConsumptionTotal network power consumption decreases• CC conserves power for originating AMS by requiring fewer retransmissions and supporting higher MCS; it consumes power from cooperator, but result is a net power savings• CC extends battery of clients w/ poor channels (where “power cost per bit” is high)
[3.5] [5] [6.5]
[Average number of users in WiFi range]
Security
Potential security concerns– Cooperator must know originator’s STID in order to detect
transmit/receive allocations - may encourage denial of service attacks
– Cooperator receives bursts from/to originator – is there risk of cooperator viewing/altering bursts?
Resolution– Resolve concern regarding denial of service attack by enabling ABS
to create “cooperation STID” when CC is implemented between two AMSs
– Bursts are encrypted and keys are never shared with cooperator, thus there is no risk of cooperator viewing/altering bursts
9
04/21/2310
Mobility
AMS can lose CC support due to mobility • Mobility does not result in lost tx opportunities for AMS or changes in
scheduling; if cooperator lost, AMS will simply tx on its own
• If AMS loses contact with cooperator, AMS will search for new cooperator
Overhead results from having to find new cooperator for AMS• Mobile AMSs shall not engage in CC
• Even semi-stationary AMSs move at times; however overhead from having to reassign cooperator small compared to gain from CC
Large number of low mobility scenarios• Stationary scenarios such as M2M
• Semi-stationary scenarios such as laptops in homes, cafés, offices, etc.
WiMAX/WiFi TDM for CC
MAP + DL Data Burst(MS & Coop check for allocations given to their Coop STID and listen for bursts)
0 1 2 3 4 0 1 2
WiMAX frame
DL subframe index UL subframe index
WiFi:Coop tx rec’d DL burst to MS. MS tx UL burst to Coop.
BS
MS
Cooperator
HARQ + UL Data Burst(MS tx burst)
UL Data Burst (If Coop successfully rec’d burst from MS, it tx it at same time)
Standards Impacts
WiFi – Peer-to-peer WiFi connectivity required– Neighbor Discovery and Cooperator Selection/Assignment
protocols need to be enabled in P2P WiFi mode
WiMAX– Enable coordinated Neighbor Discovery opportunities
–Speeds up WiFi Neighbor Discovery – saves power –Increases probability of discovery – improves cooperator selection
– Provide shared STID for originator and cooperator AMSs when engaging in CC
–Establishes cooperative relationship without sharing AMS’s STID–Allows central entity to do accounting
Summary & Recommendations
• Client Cooperation in Heterogeneous WiMAX/WiFi Networks promise
significant improvements in cell-edge user goodput and network energy
efficiency
• Next generation 802.16 standard should develop protocols to facilitate
Client Cooperation in Heterogeneous WiMAX/WiFi networks
Backup
SLS assumptions• We analyze cell-edge spectral efficiency (bps/Hz)
• WiMAX multi-cellular network analysis • cell radius = 500m
• realistic broadband channel models (Erceg-Greenstein path loss model, lognormal shadowing std=8, frequency-selective fading 4-tap channel with K-factor=1, exponential power delay profile)
• co-channel interference (only consider 1st-tier interference from neighboring ABSs) assuming reuse 1
• OFDMA signaling
• Typical WiMAX link budget
• BS antenna height = 12.5m, MS antenna height = 2m
• AMS power = 23 dBm (200 mW)
• ABS has two antennas and all AMSs have a single antenna
• SNR limit = 20 dB (i.e. any gain above this yields no goodput gain since this is max MCS level)
• ABS-to-AMS channels uncorrelated
• AMSs are located randomly throughout WiMAX cells
• Round Robin scheduling
• Gain combining of originating and cooperating AMS signals at ABS receiver
• Cooperation is for upstream traffic in UL subframes
• WiFi analysis• Receive radius = 200m (i.e. this is the AMS cluster radius)
• AMS power = 23 dBm (200 mW)
• RTS-CTS scheduling
• WiFi transmissions are only during WiMAX UL subframes
More Use Cases
Airport terminal
Airports: In airports, or any public waiting area, there will be many locations with poor signal. These can be significantly improved by receiving CC support from users in good locations.